Fix an invalid strlen comparison in ssh_message_auth_reply_default
Fix an invalid strlen comparison in ssh_message_auth_reply_default

During the transition to strncat in ssh_message_auth_reply_default,
an invalid strlen comparison was added which causes the function
to fail whenever it's called.

Signed-off-by: Andrew Collins <f6d076349fc55ec283d554dab494dedc98bc2a8e@gmail.com>
Reviewed-by: Andreas Schneider <5be00ddc76278cf6077f5047ca3384a88460c671@cryptomilk.org>

nviennot/libssh,kedazo/libssh,Distrotech/libssh,DouglasHeriot/libssh,DouglasHeriot/libssh,DouglasHeriot/libssh,robxu9/libssh,DouglasHeriot/libssh,jt1/honeypot-libssh,wangshawn/libssh,sebadoom/libssh,pouete/libssh,sebadoom/libssh,nviennot/libssh,elastichosts/libssh,jt1/honeypot-libssh,wangshawn/libssh,Distrotech/libssh,robxu9/libssh,bigcat26/libssh-mod,sebadoom/libssh,taikoo/libssh,bigcat26/libssh-mod,mwgoldsmith/ssh,elastichosts/libssh,Distrotech/libssh,mwgoldsmith/libssh,mwgoldsmith/ssh,nviennot/libssh,pouete/libssh,sebadoom/libssh,bigcat26/libssh-mod,kedazo/libssh,wangshawn/libssh,elastichosts/libssh,mwgoldsmith/libssh,jt1/honeypot-libssh,mwgoldsmith/libssh,pouete/libssh,mwgoldsmith/ssh,mwgoldsmith/ssh,wangshawn/libssh,robxu9/libssh,jt1/honeypot-libssh,taikoo/libssh,bigcat26/libssh-mod,mwgoldsmith/libssh,kedazo/libssh,taikoo/libssh,nviennot/libssh,robxu9/libssh,Distrotech/libssh,pouete/libssh,kedazo/libssh,taikoo/libssh